Spark plug



I Patented- [UNITED-I, STATES "PATENT OFFlCE SPARK PLUG Emil Kohout and Kenneth Ile'e Ingersoll, Jackson, Mich.

Application April 27, 1940, SerialNo. 332,018 8 Claims. (01. 123 -169) v This invention relates to spark plugs, one of the objects being to provide an eflective sectiona1 spark plug which can be produced at low cost and which utilizes interchangeable electrodes. A iurther object is to provide a spark plug which can be seated within the motor head where it will be maintained at a low tempera- .ture during the operation of the motor.

A still further object is to provide a spark plug which dispenses with the casing commonly used and eliminatescompression leakage usually cccurringbetween the engine head-and the spark plug casing.

A still further object is to provide a spark plug the interchangeable portions of which can be assembled readily while out of position in the motor, adjusted relative to each other and then assembled in proper relation within the motor head.

Another object is to produce a spark plug which, while utilizing interchangeable electrodes, can nevertheless be produced generally at a cost less than that of the usual spark-plug.

A iurtherobject is to provide a spark plug the parts of which are so assembled that none of In the accompanying drawing the preferred 7 form of the invention has been shown.

'In said drawing Figure l is 'a central the spark.plug and that portion oi a motor head in which it is seated.

Figure 2 is a section on line 2-2, Figure 1.

Figure 3 is a plan view of one of the compression washers.

Figure 4 is an endelevation of that end of the porcelain core with which the washer is to be assembled.

Figure 5 is a central vertical section through the electrode ring.

Figure 6 is a section through a portion of a modified form of spark plug.

Referring to the figures by characters of reference, A designates a portion of a motor head provided with a recess i the outer end of which vertical section throughhas its wall screw-threaded as shown at 2 while. its inner end has an opening I adapted to communicate with .the combustion chamber of the motor. An annular shoulder 4 is. formed in the recess about opening 3 and another annular shoulder l, which is inclined, is formed by the wall of the recess at a point between the ends thereof. I

Shoulder 4 forms a seat for a ring 6 in which are anchored grounded electrodes I. In the structure illustrated two 01' these electrodes are provided, these being oppositely' disposed and having terminals extended toward each other. It is to be understood, however, that any desired number of electrodes can be used and that the electrodes can be of any shape preferred. They are so assembled with the ring that they can be inserted readily into the opening 3 while ring I is being placed on its seat 4. The ring, when inserted downwardly, contacts with the wall or recess I. 1

The core of the spark plug has been indicated at l and can be formed of porcelain or any other suitable insulating material. The core includes a body portion 9 the diameter of, which is somewhat less than the internal diameter of recess i. From one end of this body projects a tapered extension iO centrally disposed, and that end of 30 the body 9 from which the projecting portion ill extends is tapered to provide an annular shoulder ll. One or more fins ii are extended from this shoulder and along the extension ill and,.

when the parts of the spark plug are properly assembled, these fins will bear against-ring 6 and hold it to its seat 4, as shown in Figure 1.

The outer end of the body portion 9 of core 8 A is formed with an inclined annular shoulder 13 which surrounds the base or an elongated tapered stem l4 forming a part of the core and which stem, at its outer end, is enlarged annularly as at I! to provide a shoulder i6.

A central longitudinal bore ll is extended within stern II from its outer end and terminates within the bodyportion 9 of the core. The inner end of this bore provides a tapered seat I8 located about one end of an opening it! which extends through body 9 and its extension ill at the center thereof.

, A compression gasket, indicated at 20 and which is substantially conical, is adapted to be mounted on the shoulder ii and this gasket has a central opening ii for the reception of the extension l0 and one or more recesses in the wall of the opening as at 22, for the reception of the fin or fins I2. Another compression gasket or I washer 23 is adapted to fit on the shoulder it; and

around the base of stem M and is located where it can be engaged and compressed by a gland nut 25 which is extended into recess 8 and is in engagement with the threaded portion 2.

A tubular stud 25 is mounted on the outer end iii of stem it and is provided with an enlarged base 28 from which depends an annular flange 2?. This flange is adapted to fit snugly about the enlarged portion i and after being assembled therewith, is adapted to be crimped under the shoulder it so as thus to hold the stud assembled with stem it. A screw cap'28 detachably engages stud 25 and in this cap at the center thereof is a small recess 29 for receiving the tapered end 30 of thecentral electrode 3!. This central electrode is extended downwardly within the bore i! and opening l9 and is formed with a tapered enlargement 32 adapted to bear against the seat l8 as shown in Figure 1. A firm contact between the parts can be made by tightening the cap 28 on the stud 25 and when electrode 3i is thus assembled, it will have its active end extended between the points of the grounded electrode 1 as shown.

The ring 6 which carries the grounded electrodes l is provided with notches 33 correspond ing with the recesses 22 and the fins i2 and when this ring is in position its notches are so located as to receive the Furthermore the upper end of the ring isflared, as at 36 so as to constitute an extension of the shoulder 5 on which the gasket 20 can rest.

In assembling this'spark plug the washer 23 is placed about stem i4 and said stem is then inserted through nut 24. Thereafter stud 25 is attached to the enlarged end l5 of the stem as already explained and electrode 3! is inserted into the core where it is held firmly against seat It by tightening the cap 28. Core 8 can then be inverted and washer 20 and ring 5 placed thereon with the fins extending through recesses 22 and inserted in the recess I and brought into position to allow the fins l2 to drop into the notches 33. Thereafter the gland nut 24 is tightened within the recess and this results in holding the parts of the spark plug together securely and also properly assembled with the motor head. An air space is formed between the body 9 and the wall of the recess as shown in Figure 1 at 35 and as the wall of the recess is cooled by the water surrounding it within the motor head, it will be obvious that the spark plug can be maintained at a low temperature while the motor is functioning.

As this spark plug is not provided with the usual casing, there is no danger of a leakage taking place between the casing and the motor head. Furthermore as the spark plug'is seated within the motor head, it can be kept cool as already explained. Whenever it is desired to change any of the electrodes, the change can be effected readily as will be obvious.

The central electrode 3| can be of any shape desired and also of any proportions found useful.

aesaese taking the place of the walls of the recess shown in Figure 1 and providing the shoulder St for the compression washer to and also the threads 3? for engagement by the nut it.

What is claimed is:

i. In a spark plug the combination with a member having a recess and superposed annular shoulders therein, of a ring removably seated on one of the shoulders, an electrode projecting therefrom and beyond the recess, there being a notch in the ring, a washer seated on the other shoulder, an insulating core, means on the core and insertible into the washer and the notched ring for holding said washer and ring against relative rotation, a central electrode carried by and projecting from the core, and means engaging a wall of the recess for compressing the washer between its supporting shoulder and the core.-

2. In a spark plug the combination with a memberhaving a recess open at its ends and provided with superposed interior shoulders constituting seats, of a ring detachably seated on one of the shoulders and having a notch in one face, an electrode extending from the ring and through one open end of the recess, a compression washer mounted on the other shoulder, an insulating core insertible into the recess and onto the washer, means carried by thecore and insertible into the washer and into the notch in the ring for holding said ring and washer against relative rotation, said. ring providing a seat for the washer, and means adjustably engaging the wall of the recess for compressing the washer between the core and its shoulder and the ring.

3. In a spark plug the combination with a.

' er mounted on the other shoulder, an insulating core insertible into the recess and onto the washer, means carried by the core for compressing said washer against the ring and shoulder for holding said ring and washer against relative r0- tation, said ring providing a seat for the washer, and means adjustably engaging the wall of the recess for compressing the washer between the core and its shoulder and the ring, said means including a gland nut and a compression washer interposed between the nut and the core.

4. In a spark plug the combination with a member having a recess open at its end and superposed annular shoulders within the recess, of a ring removably seated on one of the shoulders,

said ring having a notch in one face, an electrode extending from the opposite face of the ring and through one open end of the recess, an insulating cgre' insertible into the recess and having an annular shoulder, a compression washer interposed between the shoulder on the core and one of the shoulders in the recess, means carried by the core and seated within the washer and the notch in the ring for holding the washer and ring against relative rotation, means engaging the wall of the recess for holding the core against movement within the recess, and an electrode seated within and extending from one end of the core.

5. In a spark plug the combination with a member having a recess open at its end and superposed annular shoulders within the recess, of a ring removably seated on one of the shoulders.

said ring having a notch in one face, an electrode extending from the opposite face of the ring and through one open end of the recess, an insulating core insertible into the recess and having an annular shoulder, a compression washer interposed between the shoulder on the core and one of the shoulders in the recess, means carried by the core and seated within the washer and the notch in the for holding the washer and ring against relative rotation, means engaging the wall of the recess for holding the core against movement within the recess, an electrode within the core, cooperating means on the core and electrode for limiting the movement of the electrode in one direction. a threaded tubular stud secured to the core, and a screw cap engaging the stud, said cap constituting a thrust bearing for the electrode in the core. I

6. The combination with a motor head having a recess extending therethrough, the walls of the recess being water-cooled and said recess having superposed interior annular shoulders, of a ring removably mountedoh one of the shoulders and having a notch in one face, an electrode extending from the other face of the ring and through one end of the recess, a compression washer on the other shoulder in the recess, an insulating core bearing against the washer, means on the core insertihle into the washer and the notch in the ring for holding the washer and ring against relative rotation, said'ring providing a seat for a portion of the washer, an electrode seated within the core and projecting therefrom adjacent to the first named electrode, and means for detachably securing the core and its electrode against relative movement.

'l. The combination with a water-cooled motor head having a recess extending therethrough provided with spaced interior annular shoulders, of a ring detachably seated on one of the shoulders and having a notched face, a grounded electrode extending from the opposite face of the ring and through one end of the recess, a compression washer supported on the other shoulder and on the ring. an insulating core inser-tible into the recess and into the washer and ring, means on the core and seated in the washer and ring for holding them against relative rotation, and anelectrode carried by and extending from the core.

8. The combination with a water-cooled motor head having a recess extending therethrough provided with spaced interior annular shoulders, of a ring detachably seated on one of the shouldersand having a notched face, a grounded electrode extending from the opposite face of the ring and through one end of the recess, a compressionwasher supported on the other shoulder and on the ring, an insulating core insertible into the recess and into the washer and ring, means on the core and seated in the washer and ring for. holding them against relative rotation, an electrode removably seated within and projecting from one end of the core, a threaded stud connected to the core at one end, and a screw cap eng n the stud and constituting a thrust hearing for the electrode in the core.

EMILKOHOUT. KENNETH LEE INGERSOLL. 

